Sheath-dilator system and uses thereof

ABSTRACT

A medical device includes a sheath having a proximal end and a distal end, the sheath having an opening at both the proximal end and the distal end, and a removable dilator having a distal end and a proximal end, the dilator having at least one blood detector disposed on a tapered portion of the distal end of the dilator, the dilator positionable within the sheath such that the tapered portion of the distal end of the dilator extends through the opening in the distal end of the sheath, the proximal end of the dilator extends through the opening in the proximal end of the sheath, and at least a portion of the at least one blood detector is adjacent to the distal end of the sheath.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalPatent Application Ser. No. 61/486,637, filed May 16, 2011, which isincorporated herein in its entirety by reference thereto.

TECHNICAL FIELD

The present invention relates generally to a sheath-dilator system foruse in surgical procedures.

BACKGROUND

In endoscopic and endovascular surgery, when access to hollow vessels isrequired via a conduit suitable for transporting or engaging therapeuticequipment and materials, introducer sheath-dilators are routinely used.Typically in endovascular surgery, the dilator and the introducer sheathhave radiopaque characteristics to aid in visualization of these itemswithin the body. Additionally, the introducer sheath may use radiopaquemarkers on the tip. These markers provide an indicator of tip locationin the body when viewed fluoroscopically. The radiopaque tip is commonlycomprised of a metal band, made of a radiopaque material such as gold onthe distal tip of the introducer sheath. Such materials maysubstantially increase the cost associated with the production of suchdevices and may provide undesirable geometric constraints that createobstacles in connection with delivering therapeutic equipment throughthe introducer sheath, particularly when such equipment or materials arenon uniform in size and shape.

SUMMARY

The present invention provides a sheath dilator system and methods forusing the same. In some embodiments of the present invention, a sheathdilator includes a blood detector, which may be used to calibrate thelocation of the sheath-dilator system with respect to an artery.

In accordance with exemplary embodiments, a medical device includes: asheath having a proximal end and a distal end, the sheath having anopening at both the proximal end and the distal end; and a removabledilator having a distal end and a proximal end, the dilator having atleast one blood detector disposed on a tapered portion of the distal endof the dilator, the dilator positionable within the sheath such that thetapered portion of the distal end of the dilator extends through theopening in the distal end of the sheath, the proximal end of the dilatorextends through the opening in the proximal end of the sheath, and atleast a portion of the at least one blood detector is adjacent to thedistal end of the sheath.

The dilator may include a blood inlet opening disposed on the taperedportion, the blood inlet opening having an elliptical cross-section whenviewed along a longitudinal axis of the dilator.

The dilator may include a blood inlet opening disposed on the taperedportion, the blood inlet opening having a crescent-shaped cross-sectionwhen viewed along a longitudinal axis of the dilator.

The sheath may include one or more depth indicators affixed thereto.

The at least one blood detector may include a blood inlet opening influid communication with a blood outlet at the proximal end of thedilator.

The at least one blood detector may be a pressure sensor.

The at least one blood detector may be a flow sensor.

The at least one blood detector may be a tissue type sensor.

The sheath may include a hub at the proximal end of the sheath, and thedilator may include a hub at the proximal end of the dilator, the sheathhub releasably engaged with the dilator hub.

The blood outlet may be in the dilator hub.

The dilator may include at least one opening at the distal tapered end,the at least one opening in fluid communication with one or more lumenswithin the dilator, the one or more lumens in fluid communication with aport in the dilator hub, whereby liquid is transferable between theopening in the distal tapered end of the dilator and the port in thedilator hub.

The at least one sensor may be connected to a control system and adisplay unit.

The depth indicators may include graduation marks.

The medical device may further include a luer connector extending fromthe port in the dilator hub, the luer connector creating a fluid pathwaybetween the port and at least one of a 2 and 3 way tap.

The dilator may include an internal lumen extending the entire length ofthe dilator and adapted for tracking over a guide wire.

The transition between the distal end of the sheath and the dilator maybe substantially smooth.

The sheath hub may include an interface connectable to an endovasculardevice.

The endovascular device may be a closure device.

The medical device may further include at least one sensor on the outersurface of the sheath.

The medical device may include a linear array of sensors located alongthe outer surface of the sheath.

The linear array of sensors may be an array of tissue type sensors.

The at least one sensor may include a pressure sensor.

The medical device may include one or more radiopaque markers positionedon the dilator.

In accordance with exemplary embodiments, a medical device includes: asheath having a proximal end and a distal end, the sheath having anopening at both the proximal end and the distal end; and a removabledilator having a distal end and a proximal end, the dilator beingpositionable within the sheath such that the tapered portion of thedistal end of the dilator extends through the opening in the distal endof the sheath, the proximal end of the dilator extends through theopening in the proximal end of the sheath, wherein the dilator furtherincludes a plurality of flushing ports disposed adjacent the distal endof the sheath when the dilator is positioned within the sheath, and aplurality of detector ports, separate from the flushing ports, beingdisposed on a tapered portion of the distal end of the dilator.

At least one of the detector ports may have an elliptical cross-sectionwhen viewed along a longitudinal axis of the dilator.

At least one of the detector ports may have a crescent-shapedcross-section when viewed along a longitudinal axis of the dilator.

In accordance with exemplary embodiments, a method of positioning amedical device includes: inserting a distal end of a dilator releasablyengaged with a sheath having depth indicators thereon into an artery,the dilator including at least one blood detector positioned on atapered portion of the distal end of the dilator, the distal end of thedilator extending through an opening in the distal end of the sheath;monitoring the blood detector for a signal indicating entry of the blooddetector into the artery contemporaneously with inserting the dilatorinto the artery; and referencing the position of the sheath with respectto the artery based on the location of the sheath with respect to thepatient upon generation of the signal indicating entry of the blooddetector into the artery.

The blood detector may include a blood inlet opening disposed on thetapered portion, the blood inlet opening having an ellipticalcross-section when viewed along a longitudinal axis of the dilator.

The blood detector may include a blood inlet opening disposed on thetapered portion, the blood inlet opening having a crescent-shapedcross-section when viewed along a longitudinal axis of the dilator.

The at least one blood detector may be a blood inlet opening in fluidcommunication with a blood outlet at the proximal end of the dilator.

The sheath may include a hub at the proximal end of the sheath and thedilator comprises a hub at the proximal end of the dilator, the dilatorreleasably engaged with the sheath via a connection between the dilatorhub and the sheath hub.

In accordance with exemplary embodiments of the present invention, amethod of positioning a medical device includes: inserting a distal endof a dilator releasably engaged with a sheath having depth indicatorsthereon into an artery, the dilator including at least one blooddetector positioned on the distal end of the dilator, the distal end ofthe dilator extending through an opening in the distal end of thesheath, wherein the dilator further includes a plurality of flushingports disposed adjacent the distal end of the sheath when the dilator isengaged with the sheath, and a plurality of detector ports, separatefrom the flushing ports, being disposed on a tapered portion of thedistal end of the dilator; monitoring the blood detector for a signalindicating entry of the blood detector into the artery contemporaneouslywith inserting the dilator into the artery; and referencing the positionof the sheath with respect to the artery based on the location of thesheath with respect to the patient upon generation of the signalindicating entry of the blood detector into the artery.

At least one of the detector ports may include a blood inlet openingdisposed on the tapered portion, the blood inlet opening having anelliptical cross-section when viewed along a longitudinal axis of thedilator.

At least one of the blood detectors may include a blood inlet openingdisposed on the tapered portion, the blood inlet opening having acrescent-shaped cross-section when viewed along a longitudinal axis ofthe dilator.

The method may further include flushing a saline solution through theflushing ports.

At least one blood detector may include a blood inlet opening in fluidcommunication with a blood outlet at the proximal end of the dilator.

The sheath may include a hub at the proximal end of the sheath and thedilator may include a hub at the proximal end of the dilator, thedilator releasably engaged with the sheath via a connection between thedilator hub and the sheath hub.

Further features and aspects of example embodiments of the presentinvention are described in more detail below with reference to theappended Figures. Details of the sheath dilator system, and usesthereof, are described herein, infra.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a sheath-dilator assembly tracked over a guidewire, in accordance with embodiments of the present invention.

FIG. 2 is a side view of the sheath-dilator of FIG. 1 advanced into anartery.

FIG. 3 is a side view of the sheath-dilator of FIGS. 1 and 2 advancedfurther into the artery.

FIG. 4 is a side view of the sheath-dilator of FIGS. 1-3 post withdrawalof the dilator component from the system, in accordance with embodimentsof the present invention.

FIG. 5 shows a schematic of a dilator hub with a blood signal portconnected to a syringe in accordance with embodiments of the presentinvention.

FIG. 6 is an isometric view showing a blood inlet hole behind taperedtip of dilator, in accordance with embodiments of the present invention.

FIG. 7 illustrates cross-sectional end views of various dilators havingdistinct blood inlet hole configurations in accordance with embodimentsof the present invention.

FIG. 8 is an isometric and front view of a sheath-dilator having anelliptical blood inlet hole on the tapered section of the dilatorportion in accordance with embodiments of the present invention.

FIG. 9 is a cross section of a dilator with a multi-lumen configurationin accordance with embodiments of the present invention.

FIG. 10 is a side view and a cross sectional view of a multi-lumendilator having flushing holes in accordance with embodiments of thepresent invention.

FIG. 11 illustrates a sheath-dilator having blood pressure sensors inaccordance with embodiments of the present invention.

FIG. 12 shows a sheath assembly having sensors connected to a controlunit and a display in accordance with embodiments of the presentinvention.

FIG. 13 shows an isometric view of a sheath having embedded sensors inaccordance with embodiments of the present invention.

FIG. 14 illustrates a hub for a dilator in accordance with embodimentsof the present invention.

FIG. 15 illustrates another hub for a sheath-dilator system inaccordance with embodiments of the present invention.

FIG. 16 shows a sheath dilator system that includes radiopaque markersin accordance with embodiments of the present invention.

FIG. 17 shows a sheath dilator system that includes radiopaque markersin accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 1. General Description ofCertain Embodiments of the Invention

As described herein, the present invention provides a sheath-dilatorsystem (also referred to herein as a “device”). Such, a device is usefulfor insertion and removal of fluids and introduction of medical devicesand systems, such as devices and systems used in arterial closureoperations.

Embodiments of the present invention are specially adapted to provide anoperator with an indication of the position of the introducer sheathwith respect to a vessel. Once the operator knows the location of thetip of the sheath, the operator may advance the sheath-dilator assemblyinto the vessel accurately at fixed distance inside a vessel.Embodiments of the present invention provide various mechanisms forindicating when the introducer sheath enters a vessel and for monitoringthe penetration depth subsequent to that entry, including in someembodiments a passive detection system.

In accordance with embodiments of the present invention, a medicaldevice is provided that includes a sheath and a dilator. The sheath hasa proximal end and a distal end each of which include an opening. Thesheath also includes one or more depth indicators affixed thereto. Thedilator is removably positioned within the sheath and includes a distaltapered end, a proximal end, and at least one blood detector. Thedilator is positioned within the sheath such that the distal tapered endextends through the opening in the distal end of the sheath and theproximal end of the dilator extends through the opening in the proximalend of the sheath. At least a portion of the at least one blood detectoron the dilator is adjacent to the distal end of the sheath.

Some embodiments of the present invention provide a method ofpositioning a medical device that includes a sheath and a dilator.Embodiments of the present invention according to those methods requireinserting a distal tapered end of a dilator releasably engaged with asheath having depth indicators thereon into an artery. The dilatorincludes at least one blood detector positioned on the distal end of thedilator and extending through an opening in the distal end of thesheath. The method further requires monitoring the blood detector for asignal indicating entry of the blood detector into the arterycontemporaneously with inserting the dilator into the artery andrequires referencing the position of the sheath distal tip with respectto the artery based on the location of the sheath with respect to thepatient upon generation of the signal indicating entry of the blooddetector into the artery.

2. Aspects Embodied by the Figures

Other aspects, features and advantages of the presently disclosedsheath-dilator system will become apparent from the following detaileddescription taken in conjunction with the accompanying drawing, whichillustrate, by way of example, embodiments of the presently disclosedsystems and methods.

Referring now to the drawing figures, wherein like references numeralsidentify similar, identical or corresponding elements, embodiments ofthe presently disclosed sheath-dilator system are described.

As demonstrated in FIGS. 1-4 embodiments of the present inventionprovide a system for positioning the sheath tip a fixed distance withina blood vessel through a blood signaling system on the dilatorcomponent. The sheath-dilator 100 is inserted through a patient's skin114 and the underlying tissue layers to reach a vessel 115 such as afemoral artery. The system may be inserted specifically such that theangle of insertion is composed of a lateral component that opposes thedirection of flow of the blood within the vessel 115 as demonstrated inFIG. 1. As further described below, doing so will allow the operator toknow the exact position of the sheath tip in relation to the arteriotomyin the vessel wall, thereby allowing the operator to advance the sheathtip a specific, required distance, for example 20 mm, inside the arteryby referencing depth indicators 107, which may be graduated markings onthe outer surface of the sheath. The graduated markings on the sheathwill be referenced against the skin surface when the initial bloodsignal is observed.

With this reference point fixed, the user will then be able to advancethe sheath the required distance inside the artery by advancing thegraduated makings this distance against the same reference point on theskin surface.

FIG. 1 provides a side view of the initial stage in the processdescribed above. FIG. 1 demonstrates a cross-sectional side view ofvessel 115 and a side view of sheath-dilator 100 entering the patient'sskin 114. The sheath-dilator system 100 is tracked over a guide wire 101that is left in place once an introducer sheath used for the maininterventional procedure is removed from the femoral artery 115, inaccordance with embodiments of the present invention. The lumen in thedilator through which the guide wire travels fits guide wire 101 atdistal tip portion 104 via a hole (see holes 506, 606, and 806 at thedilator tips shown in FIGS. 5, 6, and 8 respectively) such that thedilator freely moves on the wire, yet minimizes blood leakage around thewire into the lumen through which the wire extends. In accordance withsome embodiments, following removal of the initial introducer sheath andprior to insertion of sheath-dilator 100, manual pressure is applied tothe wound site to minimize blood loss during this sheath exchange.Subsequently, sheath-dilator 100 is tracked over guide wire 101 and downthrough the tissue tract towards the artery 115. It should be understoodhowever, that the sheath dilator system 100 may be used without sheathexchange in accordance with example embodiments.

Sheath-dilator 100 includes a dilator 102 removably positioned withinsheath 103. The distal tapered tip 104 of dilator 102 extends through anopening in the distal end 106 of sheath 103. The dilator assists in thedelivery of the introducer sheath by the most atraumatic means. Thedilator includes blood inlet holes 105, which help detect blood flow andhence entry into artery 115. The blood inlet holes 105 are particularlysuitable for blood detection in view of their location on the taperedsection of dilator 102. As discussed herein the blood inlet holes may beused for the insertion of a contrast agent, the detection of which mayalso be used to indicate dilator and sheath location. The sheathcontains graduation marks 107, which help indicate and track theinsertion depth of the sheath into the artery once an entry referencepoint is established as described above and as further discussed below.The graduation marks 107 indicated and track insertion positionaccurately when the sheath 103 and the dilator 102 are held connected toeach other in a fixed relative position, such that the sheath 103 doesnot move relative to the dilator 102 during insertion. The embodimentdemonstrated in FIG. 1 also includes a hub 108 on the proximal end ofsheath 103. Hub 108 includes an opening through which dilator 102 isinserted. Dilator 102 also includes hub 109 at the proximal end ofdilator 102. Hub 109 is releasably engageable with hub 108 in accordancewith various embodiments of the present invention. The releasableengagement may be achieved through various mechanisms such as a twistand lock system, external latches, threaded engagement, or otherconnection systems. This embodiment also demonstrates blood outletopening 110 located on hub 109. Blood outlet 110 signals blood flowemanating from entry of blood into inlet 105 after inlet 105 passes intothe interior region of femoral artery 115.

The embodiment of the present invention depicted in FIG. 1 furtherdepicts a port 111 located on hub 108. Tube 112 connects port 110 toluer connector 113. Luer connector 113 provides two connection sites116. The luer connector further includes a valve 117 for controllingflow between systems connected at the connection sites 116 to port 110through tube 112 and connector 113. Accordingly, connector 113 providesvarious insertion and extraction fluid channels.

FIG. 2 provides a side view of the sheath-dilator of FIG. 1 advancedinto femoral artery 115 and advanced further along guide wire 101. Asdemonstrated in FIG. 2, an operator advance the distal tapered tip ofthe dilator through the arteriotomy in artery 115 until the blood inletholes 105 are inside of the artery. The operator is apprised of theentry of blood inlet holes 105 into the artery because entry of theholes in the artery initiates an arterial pulsatile flow of bloodthrough the inlet holes 105 into one or more channels within the dilatorand out of blood outlet 110. Blood 201 flowing out of outlet 110confirms entry of the inlet holes 105 into artery 115. Furthermore,because the blood inlet holes are adjacent to the distal tip 105 ofsheath 103, the blood indicator signals the entry of the sheath into theartery. Once the operator knows that the sheath has entered or issubstantially at the point of entry into the artery 115, the operatormay reference a specific mark 107 on the sheath 103 adjacent to thepatient's skin 114. Accordingly, the blood flow effectively calibratesthe indicators 107.

As shown in FIG. 3 the operator may continue advancing the sheathdilator 100 down the guide wire and further into the artery and thedepth of penetration will be indicated by the displacement of the sheathfrom the referenced entry indicating mark 107 to any subsequentindicator 107.

FIG. 4 is a side view of the sheath 103 shown in FIGS. 1-3 postwithdrawal of the dilator component 102 from the sheath-dilator system100, in accordance with embodiments of the present invention. Aftersheath 103 is correctly positioned within artery 115 (i.e. at therequired depth for any subsequent procedures), the dilator may bedisengaged from the sheath hub 108 and removed from the patient andsheath 103. As such, another device, such as a closure device, oranother endovascular device, may be tracked down the sheath. The sheathhub 108 and body of the closure device are engageable in accordance withembodiments of the present invention. In some embodiments, the sheathhub may connect to a closure device via a snap fit feature. In otherembodiments, the sheath hub may include a slide and rotate channel forengaging the closure device. Such a channel may be the same channel usedto engage the dilator hub. Once the sheath hub is engaged with a closuredevice the whole assembly may be retracted using the calibrated sheathdepth indicators 107 to locate an implant deployable by the closuredevice against the inner wall of the arteriotomy. The closure device maythen be cycled to secure the implant to the wall of the artery, therebyaffecting an immediate seal. The closure device sheath assembly may thenbe removed from the tissue tract. A closure device as provided in any ofU.S. patent application Ser. No. 11/413,636, filed Apr. 28, 2006 andissued Jul. 23, 2010 as U.S. Pat. No. 7,753,935, Ser. No. 12/637,948,filed Dec. 15, 2009, Ser. No. 12/749,729, filed Mar. 30, 2010, Ser. No.12/139,926, filed Jun. 16, 2008, and Ser. No. 12/982,852, filed Dec. 30,2010, and U.S. Provisional Patent Application Ser. No. 61/605,093, filedFeb. 29, 2012, all of which are hereby incorporated by reference hereinin their entireties, may be provided, as well as other closure devicesor other medical devices.

FIG. 5 shows a schematic of a dilator hub with a blood signal portconnected to a syringe in accordance with embodiments of the presentinvention. Dilator 503, like dilator 103 in FIGS. 1-3 may be engageablewith a sheath to form a sheath dilator system according to embodimentsof the present invention. Dilator 503 includes blood inlet holes 505,which provide a blood signal indicating entry into an artery. Dilator503 also includes an opening 506 at the distal tip of the dilator 503.Opening 505 may be in fluid communication with opening 510 in hub 509attached to the proximal end of dilator 503. Opening 510 may include atube 501 that includes a connector 511, such as a luer connector.Connection 511 may releasably connect to a device such as syringe 502,which may be used to inject fluid 507 into an artery through opening 506and/or 505 or may conversely be used to controllably extract blood fromthe artery. Additionally, the connector may be used to connect thedilator 503 with a syringe 502 containing saline, which may be used toflush the dilator lumen out and clear the dilator lumen(s) of anyremaining air, and ensure that all ports are open. This avoids potentialto introduce air emboli into the blood.

FIG. 6 is an isometric view of a sheath blood dilator in accordance withembodiments of the present invention. The dilator includes an opening606 for tracking the dilator down a guide wire. The dilator alsoincludes a blood inlet hole 605 behind the tapered tip 604 of dilator602 in accordance with embodiments of the present invention. In thisembodiment the blood inlet hole 605 s are located on the O.D. of thedilator. The blood inlet hole in accordance with this embodiment islocated immediately distal to the distal tip of sheath 603. These holesare in communication through the dilator tube, via at least a singlelumen, or a multi lumen tube, with at least one hole the proximal hub ofthe dilator. The communication allows fluids, such as blood in the caseof penetration into an artery through an arteriotomy, to flow. The holeswhen used in an endovascular procedure, will allow the user to know whenthe holes enter the artery, as the holes will provide a conduit for thearterial blood to flow through the dilator tube and exit the port on theproximal dilator hub. Given the relationship of the introducer sheath,which is operably connected to the dilator and hub, the user will have ameans of knowing the location of the introducer sheath tip relative thearteriotomy as described above. Accordingly, indicators 607 may beappropriately referenced based on their location with respect to theuser's skin. The inlet holes may be provided through a variety ofmethods according to embodiments of the present invention, includingpunching the holes into a dilator extrusion during a secondarymanufacturing operation. The dilator may include variants of thelocation, size and shape of the blood inlet holes in accordance withvarious embodiments of the invention, one of which is provided in FIG.7.

FIG. 7 illustrates cross-sectional end views of various dilators havingdistinct blood inlet hole configurations in accordance with embodimentsof the present invention. Some embodiments of the present inventionincorporate one of the following: two holes 704 and 705 in a dilator 701at 180 degrees to each other; three holes 706, 707, and 708 in dilator702 at 120 degrees to each other; or four holes 709, 710, 711, and 712in dilator 703 at 90 degrees to each other. The dilator may require morethan one blood inlet hole to mitigate against the risk of this holebecoming inadvertently blocked e.g. manual digital pressure on the woundsite might block or occlude a hole. With any of these single lumenoptions, the blood signalling lumen also accommodates the guide wire.

FIG. 8 is an isometric and front view of a sheath-dilator having an ovalor elliptical blood inlet hole on the tapered section of the dilatorportion in accordance with embodiments of the present invention. Inaccordance with this embodiment, blood inlet holes 805 are located alongthe tapered section 804 of dilator 802. The dilator extends throughsheath 603 having depth indicators 607 located thereon. Some benefits ofsuch embodiments include the fact that the blood entry holes 805 are inline with the direction of the arterial blood flow, which may increasethe potential for a stronger blood signal. Having these entry ports 805elliptical (or other suitable shape) allows the opening to be kept lowin profile, as shown in the front on view of FIG. 8, as compared to,e.g., a circular port. This is advantageous because it reduces thelength of skive in front of the opening 805, shown in the isometric viewof FIG. 8. Reducing this skive length reduces the potential of bleedinginto the perivascular space during insertion. This bleeding occurs whenthe skive is both intra- and extra-arterial during insertion.Additionally, such an embodiment allows the blood signal lumens to beindependent of the guide wire lumen 806. In accordance with someembodiment of the present invention, a single lumen in the dilator tubemay provide passageways to both the guide wire and fluid simultaneously.In such embodiments, the inlet holes may be formed, for example, as partof an RF tipping process for the forming the tapered tip. If the dilatoris tracked into an artery which has an I.D. very close to or the same asthe dilator O.D, then having the blood inlet lumen on the taperedsection lowers the risk of the blood inlet hole being blocked orobstructed by the wall of the artery. Although the entry holes are ovalor elliptical, it should be understood that other advantageouscross-sectional geometries, for example, crescent-shaped entry holes

FIG. 9 is a cross section of a dilator with a multi-lumen configurationin accordance with embodiments of the present invention. The dilator 902according to this embodiment includes a lumen 901 for tracking dilator902 down a guide wire. The dilator also includes two blood signal lumens903 for transporting blood from an artery to a proximal end of thedilator. As demonstrated the lumen for any of such features, may havegeometries other than purely circular geometries. Such lumen may have anoval/elliptical shape, a crescent-shape, or any other, e.g., irregular,shapes in accordance with various embodiments of the present invention.

FIG. 10 is a side view and a cross-sectional view of a multi-lumendilator having flushing holes in accordance with embodiments of thepresent invention. The dilator 1001 includes a plurality of openings1004 in the tapered section of the dilator. In addition, the multi lumendilator may incorporate additional flushing holes 1003 in addition tothe blood entry holes. These flushing holes may be used to flush salineor contrast media down through the dilator independent of the bloodlumens. Accordingly, the holes may be used as flushing conduits forsaline and contract and/or as blood signal holes. Moreover, openings1004 may be dedicated blood inlet/detection ports separate andindependent of holes 1003 configured as flushing ports.

FIG. 11 illustrates a sheath-dilator having blood pressure sensors inaccordance with embodiments of the present invention. Another option foraccurately positioning the sheath tip would be to incorporate an activeblood detector such as one or more sensors 1101 into the wall of thedilator component. The sensors may include, but are not limited to,blood pressure sensors, tissue type sensors, and flow sensors inaccordance with embodiments of the present invention. The sensor mayinclude other types of sensors capable of detecting blood flow. Thesensor(s) 1101 may be connected to a control unit 1103 via a microelectrical wire or fiber-optic cable, which would travel back up throughthe I.D. of dilator 1106 and would interface with the control unit 1103and a display unit 1102. Sensor(s) 1101 detect changes associated withthe increase in pressure or flow due to penetration of the dilator tipinto the lumen of the femoral artery as the sheath dilator systemtravels down guide wire 1107 into such an artery. As noted above, thedilator may incorporate one or more sensors and the sensors may bearranged in a linear arrangement extending longitudinally along thedilator or the sensors may be arranged in a configuration laterallytraversing dilator 1106. In some embodiments, a distal sensor ispositioned on the dilator to indicate when it enters into the bloodstream and another sensor is positioned immediately adjacent to thedistal tip of the sheath. When the sensor adjacent to the distal tip ofthe sheath enters the blood stream, the change detected by the sensorindicates to the operator that the sheath tip is positioned at thearteriotomy puncture site. Such an active system may be provided withembodiments of the sheath dilator system that also include engageablehubs 1105 and 1108, port 1109, tube 1110, and connector 1111, similar tothose described with previous embodiments of the present invention.

FIG. 12 shows a sheath assembly having sensors connected to a controlunit and a display in accordance with embodiments of the presentinvention. In this embodiment, the sheath 1104 includes sensors 1201located thereon. Sensors 1201 provide alternative depth indicators tothe passive graduation marks demonstrated in earlier embodiments. Thesensors may be connected to control unit 1103 and display unit 1102 viaa micro electrical wire or a fiber optic cable and may operate inconcert with the sensors located on the dilator, such sensors 1201 areautomatically activated by the detection of blood flow via the sensorson the sheath. Sensors 1201 may also be calibrated with respect to oneanother such that the distance between the sensors is known and suchthat the changes associated with penetrating the skin of the patient,such as pressure changes may be referenced with respect to other sensorsto indicate the depth of penetration since entry into an artery via anarteriotomy by the sheath. Such sensors may continue to provide outputafter the dilator is removed and a device, such as a closure device isattached to the sheath. When a closure device is attached to the sheathsensors 1201 may provide feedback in connection with positioning theclosure device accurate with respect to the arteriotomy of the vessel inorder to deploy the closure device at the optimal location.

FIG. 13 shows an isometric view of a sheath having embedded sensors asdemonstrated in FIG. 12 in accordance with embodiments of the presentinvention. The sensors may be provided in an integral fashion withrespect to sheath 1104 such that they maintain the normal outer diameterof the sheath. Sensors 1201 may be electrically connected to one anothervia connection 1301. As noted above, the sensors may include, but arenot limited to, pressure sensors and flow sensors. The sensors may beembedded into the wall of the sheath during the extrusion process. Thesensors may be provided as an alternative to or in conjunction with thegraduation marks disclosed in various embodiments of the invention.

FIG. 14 illustrates a hub for a dilator in accordance with embodimentsof the present invention. Extension 1403 is representative of a dilatorused in accordance with embodiments of the present invention. Hub 1408is connected to at least one of the dilator 1403 extending therefrom.Hub 1408 facilitates fluid communication between the extension 1403 andany fluid source or reservoir (not shown) maintained at the luerconnection site 1416. In the absence of such a source or reservoir,connection site 1416 may be capped by cap 1419 to prevent contamination.In the presence of such a source or reservoir, fluid may be added orremoved from the dilator or sheath by traveling from the connection site1416, down tube 1412, into port 1411, and through elbow 1418 at the topof hub 1408. The hub, port, tube, and connection site may all becomposed of plastic in accordance with various embodiments of thepresent invention. The hub, elbow, and port may be manufactured using amolding process such as an injection molding process.

FIG. 15 illustrates another hub for a sheath-dilator system inaccordance with embodiments of the present invention. The hubillustrated in FIG. 15 is a multi-part hub with multiple input/outputfluid channels. In accordance with embodiments of the present invention,a lower hub portion 1508 may be adjacent to sheath 1503. Hub 1508 mayprovide a fluid communication path between a source or reservoir (notshown) via tube 1512 and connector 1517. Connector 1517 may be amulti-way connector such that 2, 3, or more sources or reservoirs may bebrought into fluid communications with sheath 1503. The depictedconnector 1517 allows two sources to be connected at sites 1516, one ofwhich is capped via cap 1519 in the illustrated embodiment. Connector1517 also includes a valve controlled by valve stem 1520, the rotarymotion of which allows or prevents any source or reservoir maintained ateither of the connections sites from being in fluid communication withtube 1512 and hence hub 1508 and sheath 1503. Upper hub portion 1509 mayprovide a distinct fluid communication path via elbow 1518 and tube1522. As demonstrated in FIG. 15, tube 1522 (and similarly tube 1512)may include a single-way connector such as connector 1526. The connectormay include a cap 1529 when no source or reservoir is present. Theconnector 1526 may be a luer type connector. Each of the connectors 1517and 1526 and their respective tubes 1512 an 1522 may allow outward boundfluid communication (i.e. blood or other bodily fluids flowing fromsheath 1503 to the connector to achieve a blood signal indicator) orinward bound communication (i.e. fluid such as a contrast media orsaline flowing from the connector towards the sheath) in accordance withembodiments of the present invention. The upper hub 1509 may providefluid communication between a reservoir and the dilator, while the lowerhub 1508 may provide fluid communication between a source and the sheathor vice versa in accordance with embodiments of the present inventions.Accordingly, one hub may be used solely for outbound flow, particularlyflow associated with indicating entry into a vessel by outward flow ofblood through the dilator, while the other hub may be used solely forinbound flow of contrast media, saline solution, or other fluids beingintroduced into a patient. Alternatively, in some embodiments, both hubsmay facilitate bi-direction fluid communication. The hubs may also beengaged such that connection tubes 1512 and 1522 extend in the samedirection or in distinct directions in accordance with variousembodiments of the present invention. Hubs 1508 and 1509 may berotatably connected in accordance with embodiments of the presentinvention to facilitate positioning the respective connection tubes asdesired.

FIG. 16 shows a sheath dilator system that includes radiopaque markersin accordance with embodiments of the present invention. Dilator 1602may include one or more radiopaque markers in accordance withembodiments of the present invention. The markers may be positioned atspecified distances from the tapered tip 1604 of the dilator or fromspecified distances from the blood inlet hole(s) 1605 on the tapered tipof the dilator. The markers 1600 and 1601 may be positionedconcentrically on dilator 1602 and within sheath 1603. The markers maybe flush with the dilator in accordance with embodiments of the presentinvention. The markers function is to provide visual indicators to anoperator of the location of the dilator and the sheath. The markers,which may have a width of 3 mm, may provide distinct locationidentifiers. For example, the first marker 1600 may be positionedadjacent to or just short of the distal tip of sheath 1603 andaccordingly, provides a visual indicator of the location of the distaltip of the sheath to an operator. The second marker 1601 may indicatethe position of the dilator relative to the sheath distal tip. Once theproximal radiopaque marker 1601 is positioned within the arteriotomy, anoperator may be apprised of the distal tip of the sheath beingpositioned in the artery lumen and a closure device may subsequently beintroduced into the artery lumen based on this position indicativeinformation. Marker bands may be manufactured from a platinum/iridiummetal marker band which is swaged onto the circumference of the dilator.

FIG. 17 shows another sheath dilator system that includes radiopaquemarkers in accordance with embodiments of the present invention. Dilator1702 may include one or more radiopaque markers 1700 in accordance withembodiments of the present invention. The markers may have a variety ofgeometric shapes, such as a square, circle, or other shapes forming apoint in contrast to the band markers shown in FIG. 16. The markers maybe positioned at specified distances from the tapered tip 1704 of thedilator or from specified distances from the blood inlet hole(s) 1705 onthe tapered tip of the dilator. The markers may be flush with thedilator in accordance with embodiments of the present invention. Themarkers function is to provide visual indicators to an operator of thelocation of the dilator and the sheath, similar to the function ofmarkers 1600 and 1601 of FIG. 16. Marker 1700 may also be manufacturedfrom a platinum/iridium metal marker band which is swaged onto thecircumference of the dilator.

The above described embodiments of the present invention provide solelyexemplary embodiments. Moreover, the features of the particular examplesand embodiments described herein may be used in any combination. Thoseof ordinary skill in the art will appreciate that the present inventionincludes variations and modifications of the disclosed examples andembodiments are within the scope of the present invention and may becaptured by any claims provided herein or added hereto.

1. A medical device comprising: a sheath having a proximal end and adistal end, the sheath having an opening at both the proximal end andthe distal end; and a removable dilator having a distal end and aproximal end, the dilator having at least one blood inlet openingdisposed on the distal end of the dilator, wherein the blood inletopening is in fluid communication with a blood outlet at the proximalend of the dilator, and the dilator is positionable within the sheathsuch that a tapered portion of the distal end of the dilator extendsthrough the opening in the distal end of the sheath, the proximal end ofthe dilator extends through the opening in the proximal end of thesheath, and at least a portion of the at least one blood inlet openingis adjacent to the distal end of the sheath; wherein the blood inletopening is disposed on the tapered portion, characterized in that theblood inlet opening has a crescent shaped cross-section when viewedalong a longitudinal axis of the dilator. 2-3. (canceled)
 4. The medicaldevice according to claim 1, wherein the sheath further comprises one ormore depth indicators affixed thereto. 5-8. (canceled)
 9. The medicaldevice according to claim 1, wherein the sheath further comprises a hubat the proximal end of the sheath and the dilator comprises a hub at theproximal end of the dilator, the sheath hub releasably engaged with thedilator hub.
 10. The medical device according to claim 9, wherein theblood outlet is in the dilator hub.
 11. The medical device according toclaim 1, wherein the dilator further comprises at least one opening atthe distal tapered end, the at least one opening in fluid communicationwith one or more lumens within the dilator, the one or more lumens influid communication with a port in the dilator hub, whereby liquid istransferable between the opening in the distal tapered end of thedilator and the port in the dilator hub.
 12. (canceled)
 13. The medicaldevice according to claim 1, wherein the depth indicators includegraduation marks.
 14. The medical device according to claim 9, furthercomprising a luer connector extending from the port in the dilator hub,the luer connector creating a fluid pathway between the port and atleast one of a 2 and 3 way tap.
 15. The medical device according toclaim 1, wherein the dilator includes an internal lumen extending theentire length of the dilator and adapted for tracking over a guide wire.16. The medical device according to claim 1, wherein the transitionbetween the distal end of the sheath and the dilator is substantiallysmooth.
 17. The medical device according to claim 9, wherein the sheathhub includes an interface connectable to an endovascular device.
 18. Themedical device according to claim 17 wherein the endovascular device isa closure device.
 19. The medical device according to claim 1, furthercomprising at least one sensor on the outer surface of the sheath. 20.The medical device according to claim 1, further comprising a lineararray of sensors located along the outer surface of the sheath.
 21. Themedical device according to claim 20, wherein the linear array ofsensors is an array of tissue type sensors.
 22. The medical deviceaccording to claim 19, wherein the at least one sensor is a pressuresensor.
 23. The medical device according to claim 1, further comprisingone or more radiopaque markers positioned on the dilator.
 24. A medicaldevice comprising: a sheath having a proximal end and a distal end, thesheath having an opening at both the proximal end and the distal end;and a removable dilator having a distal end and a proximal end, thedilator being positionable within the sheath such that the taperedportion of the distal end of the dilator extends through the opening inthe distal end of the sheath, the proximal end of the dilator extendsthrough the opening in the proximal end of the sheath, wherein thedilator further includes a plurality of flushing ports disposed adjacentthe distal end of the sheath when the dilator is positioned within thesheath, and a plurality of detector ports, separate from the flushingports, being disposed on a tapered portion of the distal end of thedilator. 25-26. (canceled)
 27. A method of positioning a medical device,comprising: inserting a distal end of a dilator releasably engaged witha sheath having depth indicators thereon into an artery, the dilatorincluding at least one blood detector positioned on a tapered portion ofthe distal end of the dilator, the distal end of the dilator extendingthrough an opening in the distal end of the sheath; monitoring the blooddetector for a signal indicating entry of the blood detector into theartery contemporaneously with inserting the dilator into the artery; andreferencing the position of the sheath with respect to the artery basedon the location of the sheath with respect to the patient upongeneration of the signal indicating entry of the blood detector into theartery. 28-37. (canceled)